import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
 * Servlet implementation class DatabaseAccess
 */
@WebServlet("/book")
public class MessageBook extends HttpServlet {
    private static final long serialVersionUID = 1L;
    // JDBC 驱动名及数据库 URL
    static final String JDBC_DRIVER ="com.mysql.jdbc.Driver";// "com.mysql.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://localhost:3306/messagebook?characterEncoding=utf-8&useSSL=false";

    // 数据库的用户名与密码，需要根据自己的设置
    static final String USER = "root";
    static final String PASS = "123456";
    /**
     * @see HttpServlet#HttpServlet()
     */
    public MessageBook() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Connection conn = null;
        Statement stmt = null;
        // 设置响应内容类型
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();


        SimpleDateFormat ft = new SimpleDateFormat ("yyyy-MM-dd hh:mm:ss");

        String title = "Servlet版本留言板" + "当前时间为: " + ft.format(new Date());
        String docType = "<!DOCTYPE html>\n";
        out.println(docType +
                "<html>\n" +
                "<head><title>" + title + "</title></head>\n" +
                "<body bgcolor=\"#f0f0f0\">\n" +
                "<h1 align=\"center\">" + title + "</h1><hr>\n");
        try{
            // 注册 JDBC 驱动器
            Class.forName("com.mysql.jdbc.Driver");

            // 打开一个连接
            conn = DriverManager.getConnection(DB_URL,USER,PASS);

            // 执行 SQL 查询
            stmt = conn.createStatement();
            String sql;
            sql = "SELECT * FROM messagebooks";
            ResultSet rs = stmt.executeQuery(sql);
            out.println("<center>");
            out.println("<table border=2>");
            out.println("<tr>");
            out.println("<td>ID</td>");
            out.println("<td>留言人</td>");
            out.println("<td>主題</td>");
            out.println("<td>内容</td>");
            out.println("<td>留言时间</td>");
            out.println("</tr>");

            while(rs.next()){

                out.println("<tr>");
                int id  = rs.getInt("id");
                String user = rs.getString("user");
                String titles = rs.getString("title");
                String context = rs.getString("context");
                String create_time = rs.getString("create_time");

                out.println("<td>"+id+"</td>");
                out.println("<td>"+user+"</td>");
                out.println("<td>"+titles+"</td>");
                out.println("<td>"+context+"</td>");
                out.println("<td>"+create_time+"</td>");

                out.println("</tr>");
            }
            out.println("</table></center></body></html>");

            // 完成后关闭
            rs.close();
            stmt.close();
            conn.close();
        } catch(Exception e) {
            // 处理 Class.forName 错误
            out.println(e);
            e.printStackTrace();
        }finally{
            // 最后是用于关闭资源的块
            try{
                if(stmt!=null)
                    stmt.close();
            }catch(SQLException se2){
            }
            try{
                if(conn!=null)
                    conn.close();
            }catch(SQLException se){
                se.printStackTrace();
            }
        }

    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }
}